Child-proof and pharmacist-assisting reversible closure for containers

ABSTRACT

A unitary reversible closure for containers of medicine and the like is applied in one position to the container to render the container child-resistant and in such position requires a complex manipulation of the closure to release it from the container. In a second position of application to the same container, the closure seals the container but requires only a simple manipulation by the pharmacist to release it from the container, thereby lessening irritation and discomfort to the pharmacist&#39;&#39;s fingers cause by manipulating closures or caps over a period of time and saving the pharmacist considerable time in removing closures over a period of time to fill the containers.

United States Patent 1 Morris CHILD-PROOF AND PHARMAClST-ASSISTINGREVERSIBLE CLOSURE FOR CONTAINERS Inventor: Glenn H. Morris, 4203Highwood Dr., Chattanooga, Tenn. 37415 Filed: Dec. 20, 1973 Appl. No.:426,534

215/224 7 Int. Cl. B65d 55/02, B65d 85/56, A61j 1/00 I Field of Search215/206, 211, 214, 217, 215/223, 224; 220/42 C, 60 R References CitedUNITED STATES PATENTS 3/1969 Burgess 215/206 12/1971 Horvath 215/206 X[111 3,865,267 1 Feb. 11, 1975 Primary ExaminerGeorge T. Hall Attorney,Agent, or FirmBrady, OBoyle & Gates 57 ABSTRACT 1 -A unitary reversibleclosure for containers of medicine and the like is applied in oneposition to the container to render the container child-resistant and insuch position requires a complex manipulation of the closure to releaseit from the container. In a second position of application to the samecontainer, the closure seals the container but requires only a simplemanipulation by the pharmacist to release it from the container, therebylessening irritation and discomfort to the pharmacists fingers cause bymanipulating closures or caps over a period of time and saving thepharmacist considerable time in removing closures over a period of timeto fill the containers.

17 Claims, 18 Drawing Figures I 1 CHILD-PROOF AND PHARMACIST-ASSISTINGREVERSIBLE CLOSURE FOR CONTAINERS BACKGROUND OF THE INVENTION A newFederal law requires medicine containers to be equipped withchild-resistant caps or closures to avoid injury or death to curiouschildren who seek access to the contents of containers. Generally, thechildresistant closures which have been developed to satisfy therequirements of the law require a complex manipulation to release themfrom the containers, so that normally only an adult will be able to openthe container of medicine or the like. The required complex manipulationof the closure is usually a plural step movement thereof, such asturning, aligning and lifting, or pressing inwardly, turning andlifting, or some similar combination of manipulative steps. A typicalexample of the patented prior art relating to child-resistant closuresfor medicine containers is U.S. Pat. No. 3,432,058 of Mar. 11, 1969which exhibits a closure or cap for medicine bottles which must first berotated to align an internal lug thereof with a notch provided in aflange on the neck of the container, followed by a lifting of one sideof the cap while the lug is aligned with the notch. Quite a large numberof arrangements have been devised in the prior art to satisfy therequirements for a childresistant closure for medicine containers andthe above-identified patent is merely an illustrative example of theprior art.

It is customary in the interest of convenience and cleanliness ofcontainers to supply medicine containers to pharmacists with the closureelements in place thereon. This avoids separation and loss of the partsand assuresthat the interiors of the containers are in a clean conditionat the time of being filled. In the case of child-resistant closures, arather serious problem has arisen in connection with the necessity forthe pharmacist to constantly remove the safety closure from thecontainer prior to filling the latter with medicine and reclosing it.This problem concerns increasing opening time and discomfort andirritation of the fingers of the pharmacist who must manipulate theclosures during an entire working day. Because the child-resistantclosures require a series of movements or steps to release them, and arepurposely made difficult to manipulate for the protection of children,it takes the pharmacist longer to remove the safety closures from thecontainers and the pharmacists fingers by the end of the day arefrequently very sore and uncomfortable to the extent that some of theskin may actually be damaged and this slows him up even more in openingthecontainers and substantially reduces the number of containers he canfill in a day. This condition has led to many complaints by pharmacistsand thus far no satisfactory solution to this annoying problem has comeforth. With the safety closures a pharmacist can no longer fill the samenumber of medicine containers in a day as he could in the past and thisis causing an increase in medicine cost to the consumer.

Accordingly, it is the objective of this invention to completely andsatisfactorily solve the above-discussed problems of lost time andfinger irritation through the provision of a uniquely constructedreversible or combination closure for medicine containers which is firstapplied to the container so as to'seal the same against the entry ofcontamination and to maintain the container and its closure in assembledrelationship prior to use. In this first applied position of the closureelement, only a very quick and simple release procedure by thepharmacist is required for separating it from the container. This mayconsist of a simple pulling or twisting or lifting movement, such asthat customarily required to remove a bottle stopper or simple snap orscrew cap from a container. Such a procedure, even when repeated manytimes during the day, will not tend to cause any noticeable discomfortto the fingers, will not slow down the pharmacist, and will permit himto fill as many containers with safety caps as he has been able to fillin the past with non-safety caps- In a second use position of the sameclosure on the same container following the removal of the closure inits first-applied position and the filling of container with medicine,the closure becomes a child-resistant safety closure which requires amore complex manipulation in order to separate it from the container.Thus, by means of the invention, a simply unitary reversible cap orclosure alleviates the annoying problems of lost pharmacist time andfinger irritation as commonly caused by the constant handling ofchild-proof or safety caps. At the same time, due to the easyreversibility of the closure, the advantageous practice of furnishingcontainers and closures to pharmacists in assembled relationship isretained, and all of this without any appreciable cost increase.Additionally, in situations where no children are present, thecombination cap embodying the invention has the added capability ofbeing used as a simple stopper or cap without the safety feature.

It is a further object of the invention to provide any form ofchild-resistant medicine bottle closure with means for applying theclosure to a container in a nonsafety position for the stated purpose ofeliminating finger irritation and discomfort and lost time in openingcontainers on the part of the pharmacist who must manipulate theclosures time after time while filling prescriptions. In essence,therefore, the closure of the invention is a two-position closure foruse on the same container which in a first position of use is easy andquick to separate from the container and in a second position of use ismore difficult to separate from the container while providing therequired child-resistant features.

Other features and advantages of the invention will become apparentduring the course of the following description.

DESCRIPTION OF DRAWING FIGURES FIG. 1 is an exploded perspective view,partly in cross section, showing a closure element embodying theinvention and a coacting container.

FIG. 2 is a central vertical section showing the closure applied to thecontainer in a first use position.

FIG. 3 is a perspective view showing the closure applied in a second useposition to thereby constitute a child-resistant closure.

FIG. 4 is a central vertical section through the closure and containeras shown in FIG. 3 and depicting in broken lines the removal of thechild-resistant closure.

FIG. 5 is an exploded perspective view of a modified form of closure andcontainer involving a combination screw-thread and snap-on mode ofoperation.

FIG. 6 is a central vertical section showing the assembled relationshipof the closure and container of FIG. 5.

FIG. 7 is a similar sectional view illustrating the removal of thechild-resistant closure from the 'coacting container.

FIG. 8 is a perspective view of a modified'form of cap or closure whichmay be utilized instead of the caps illustrated in FIGS. 1 and 5.

FIG. 9 is a perspective view, partly in section, showing a. modifiedtype of reversible closure for medicine containers in accordance withthe invention.

FIG. 10 is an exploded sectional view of the closure shown in FIG. 9 anda coacting container.

FIG. 11 is a further cross sectional view showing the closure of FIG. 9assembled with the container in the first non-safety use position.

FIG. 12 is a central vertical section showing a further modified form ofclosure embodying the invention.

FIG. 13 is a bottom plan view of the closure shown in FIG. 12.

FIGS. 14 and 15 are similar cross sectional views showing two additionalmodifications of the invention.

FIG. 16 is a perspective view, partly broken away, of a closureembodying a further modification of the invention.

FIG. 17 is a central vertical section taken through the closure of FIG.16 with the same inverted.

FIG. 18 is a vertical section taken on line 1818 of FIG. 17.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Referring initially toFIGS. 1 to 4 of the drawings, there is illustrated a reversible closureor cap 20 for a container 21 of a type adapted to receive medicines. Theparticular container 21 illustrated is of the general type disclosed inthe. aforementioned U.S. Pat. No. 3,432,058 and the invention embodiedin the closure 20 has its child-resistant or safety aspect disclosedsubstantially in terms of the construction shown in said patent.However, it should be clearly understood that the invention whichinvolves a two position reversible closure for the same container mayemploy as a part thereof any one of avariety of types of child-resistantconstructions in combination with one or more of the structuresaccording to the invention which adapt the closure for a non-safetyapplication to the container for the convenience and comfort of thepharmacist who mustmanipulate the same.

More particularly, the closure 20 which is unitary and formed of a toughplastic, such as polystyrene, comprises a crowned generally cylindrical,although slightly tapered, plug'or stopper section 22 having a flat endwall 23. The side wall of plug section 22 is preferably provided with anexternal annular bead 24 to promote a snug engagement and snap actionwhen the plug section 22 is forced into the open mouth of container 21',as shown in FIG. 2.

The reversible closure 20 additionally comprises an enlarged flatannular wall 25 at the base of plug section 22 and projecting outwardlytherefrom substantially at right angles to-the side wall of the plugsection. This wall 25 abuts the end face 26 of container 21 when theclosure is applied thereto in either of its two use positions depictedin FIGS. 2 and 4. An annular cylindrical marginal wall 27 is attachedintegrally to the wall 25 in right angular relationship thereto and isconcentric with the plug or stopper section 22, as shown. If desired,the exterior face of the wall 27 may be grooved 4 or knurled tofacilitate grasping and twisting of the closure 20.

On the interior of the annular wall 27 and close to the open end of thehollow closure 20, there is provided a pair of diametrically opposedradially narrow arcuate lugs 28 and 29, the former of which is somewhatshorter circumferentiallythan the latter, for a reason to be described.Adjacent to the shorter lug 28, the closure 20 is equipped on theexterior of its wall 27 at its open end with a lift tab 30. In alignmentwith this lift tab and the adjacent shorter lug 28, an indicator 31 suchas an arrow or dot is visibly marked on the end wall 23 of the closurefor alignment during the removal of the child-resistant closure with acooperating indicator 32 provided on the side wall of container 21.

This container, which may be cylindrical, is equipped adjacent to itsopen end with an exterior preferably tapered flange 33 having a singlerelease notch 34 formed therein. A second annular flange 35 may beformed on the container 21 in axially spaced relation to the flange 33,the latter flange constituting the means for retaining thechild-resistant closure-in its position shown in FIGS. 3 and 4, prior torelease of the closure by a series of relatively complex movements.

In use, the medicine container 21 and child-resistant closure 20 issupplied to the pharmacist in assembled relationship, with the plug orstopper section 22 pressed into the neck of the container as shown inFIG. 2. In such position, the closure seals the container and excludescontamination and the two parts are retained together to avoidmisplacement or loss. In this first use position of the closure onthecontainer 21, only a simple single manipulation by the pharmacist isrequired to separate the parts and this can be done withoutinconvenience and without discomfort to the fingers even where theoperation must be repeated a large number of times during a working day.A mere twisting or lifting force exerted on the closure 20 will besufficient to separate it from the container in this first appliedposition shown in FIG. 2.

After filling the container with medicine, the pharmacist inverts theclosure 20 from its first use position and after aligning the indicators31 and 32, simply presses the closure 20 down onto the container. Thelonger retainer lug 29 will easily engage under the retainer flange 33,and with the parts positioned as described, the shorter lug 28 will passthrough the notch- 34 and the wall 27 may bottom on the flange orshoulder 35. Following this, the closure 20 is rotated to shift the lug28 out of alignment with the release notch 34.

In order to remove the child-resistant closure from the second appliedposition shown in FIGS. 3 and 4, it is necessary to first rotate theclosure to realign the lug 28 with the notch 34 and then to lift theadjacent side of the closure, utilizing the lift tab 30, and the closurewill then separate from the container by rocking or pivoting around thelug 29 which is engaged below the flange 33. The lug 29 is too long topass through the notch 34 and therefore the closure can be removed fromthe container only after adjustment to a rather precise location andafter two separate and distinct types of manipulation. Childrenordinarily will be unable to remove such a safety closure. However, thepharmacist can very simply separate the closure 20 from the containerwhen the closure is in its initial-use position without any discomfortor damage to the fingers. Thus the invention consists of a unitaryreversible closure having pharmacist, and the second use position of theclosure being a more difficult or complex release position to protectsmall children from poisoning.

In FIGS. 5 through 7, a modification of the invention is shown whereinthe reversible two position closure, while in the child protectingposition, is engaged with the container through a compound retainingmeans involving screw-threads in addition to the interlocking meansalready described relative to lugs 28 and 29 and the flange 33. Moreparticularly, in FIGS. 5 to 7, a container 36 having the aforementionedretainer flange 33 and release notch 34 is additionally equipped belowthe flange with screw-threads or partial screw-threads 37. A cooperatingclosure 38 has a plug or stopper section 39 which is identical inconstruction and operation to the previously-described plug section 22of closure 20. In the present embodiment, the exterior cylindrical wall40 of the closure 38 is somewhat longer axially than the correspondingwall 27 in theprior embodiment and is provided internally with theidentical lugs 28 and 29 which cooperate with the flange 33 and notch 34in exactly the same manner described in the prior embodiment.

However, in connection with the embodiment in FIGS. 5 to 7, when theclosure 38 is applied in the child-resistant position on the container36, after the shorter lug 28'has been passed through the notch 34 andthe closure engaged with the retainer flange 33, the same two lugs 28and 29 coact with the screw-threads 37 when the closure is rotated toestablish a threaded connection between the two parts, as shown in FIG.6. To remove the safety closure, the same must be reversely turned toseparate the threaded elements and the closure will then be releasedfrom the threads to the position shown in FIG. 7 where it is stillretained by the lugs 28 and 29 in the same manner described in the priorembodiment. As in the prior embodiment, to separate the closure 38 fromcontainer 36, the closure must again be rotated to align the narrowerlug 28 with the notch 34, FIG. 7, and then by lifting the tab 30, aspreviously described, the closure or cap will separate from thecontainer. It will be understood that when the closure 38 is inverted,its plug portion 39 will enter the bore of the container in theidentical manner shown and described in FIG. 2, and the resultingadvantages of the invention in terms of child safety and relief of thepharmacist from finger discomfort are identical to the previousembodiment. i

FIG. 8 shows a modified cap or closure 41 which may be utilized ineither form of the invention shown in FIGS. 1 to 4, or 5 to 7. In thisconnection, the cylindrical body portion 42 of the closure may beconstructed cooperating indicator marking32 on the container.-

When applied to the container in the first use position corresponding toFIG. 2, the bar-shaped element 43 engages within the mouth of thecontainer in the manner shown in FIG. 2 and the end wall 46 of bodyportion 42 abuts the end face 26of the container. In the second useposition for rendering the container child-resistant, the closure 41functions in the manner described for the closure 20 or the closure 38,depending upon which embodiment of the safety structure is incorporatedin the body portion 42. Actually as illustrated in FIG. 8, the bodyportion 42 contains the safety structure of the initial embodiment,FIGS. 1 through 4.

FIGS. 9 to 11 illustrate another form of closure cap 47 embodying theinvention and being applicable reversely or in two positions to-thepreviously-described container 21. In the safety or child-resistingposition of the closure, not shown in FIGS. 9 to 11, the constructionand operation is substantially identical to the initial embodiment. Moreparticularly, the closure 47 comprises a cylindrical side wall 48divided into two oppositely facing sections by a transverse wall orpartition .49. On one side of this partition, the closure 47 is equippedwith the previously-described elements 28, 29 and which coact with thedescribed elements 33 and 34 of the container 21 in the manner shown inFIGS. 1 to 4. On the other side of the partition 49, the closure 47 hasits cylindrical wall provided with an internal annular bead 50 which islocated close to the adjacent end of the closure. This head is adaptedto snap over the retainer bead 33 of the container whereby the wall 49will abut the end of the container and the two parts will be assembledfor easy separation by the pharmacist without finger discomfort. Whenthe closure is reversed and applied on the same container 21, in thechild-defeating mode, its removal will be more complicated, asdescribed.

FIG. 12 shows a further modification of the invention wherein acontainer closure 51 constructed simiarly to the closure 47 possessesthe same elements 28, 29, 30 and 49 already described. These elementscoact with the container 21 to defeat child entry into the container asdescribed previously. The opposite end of the container 51, however, inlieu of the head 50, possesses a pair of equally sized diametricallyopposed internal lugs 52 of slightly lesser radial thickness than thelugs 28 and29. The thickness of the lugs 52 or the diametrical distancebetween them is such that the two lugs may snap' over the flange 33 ofthe container when the clo sure 51 is applied thereto in the useposition for easy release illustrated in FIG. 11 for the similar closure47 having the snap bead 50.

FIG. 13 illustrates the face of the divider wall 49 remote from thesafety structure'and this face is visible to the user when applying thesafety cap to a container or removing it. Consequently, this face of thewall 49 carries an alignment indicator 53 for the smaller lug 28 andsuitable instruction indicia 54, if desired.

FIG. 14 shows a slight variation in a closure 55 of the construction inFIG. 12. In FIG. 14, the cylindrical wall portion 56 of the closure onthe side of divider wall 49 remote from the safety structure is'formedthin so as to be relatively flexible. In this instance, the two opposedidentically-sized lugs 57 are relatively thicker radially than the lugs52 although still thinner than the safety lugs 28 and 29. When appliedover the container 21 or flange 33 as illustrated in FIG. 11, the thinwall portion 56 will yield to allow the lugs 57 to snap into easilyreleasable interlocking engagement with the flange 33.

FIG. shows another modified cap or closure 58 whose safety section andcomponents are also identical to the previously-described forms andtherefore need not be redescribed. In this formof the invention, themeans to retain the closure 58 in the first or non-safety use positionfor the convenience of the pharmacist, FIG. 11, consists of a relativelythin elastic cylindrical wall 59 on the side of thedivider wall 49remote from the safety structure. When applied over the flange 33 of thecontainer, the thin wall 59 will bulge outwardly and form a snug butreadily separable connection with the container so that the pharmacistcan separate the closure easily from the container without fingerdiscomfort. The instructional indicia 54 and indicator 53 shown in FIG.13 is also applicable to the two embodiments of the closure shown inFIGS. 14 and 15.

FIGS. 16 to 18 show a further form of container closure possessing thesame basic combination of the invention. More particularly, in thesefigures, the cap or closure 60 is equipped at one end with the describedelements 28, 29 and 30, which form the essence of the child-defeatingmode of operation. On the other end of the closure divided by atransverse wall 61, there is provided a bar-like plug or stopper element62 similar to the element 43 in FIG. 8 and serving the same purpose asthe element 43 during use in the manner illustrated by FIG. 2. Inaddition to the plug element 62, the same end of the closure 60 has anannular skirt or wall 63 provided with an internal annular bead 64 andthese elements surround the bar-like plug 62 in spaced relation theretoas shown in the drawings. This arrangement enables the closure 60 to beapplied to the container 21 in the first use position with the plugelement 62'inside of the container neck, FIG. 2, and the skirt 63external to the neck, FIG. 11, with the bead 64 engaged below theretainer flange 33. Again, the pharmacist may separate the closure fromthe container by a simple manipulation to save his or her fingers fromdiscomfort.

The terms and expressions which have been employed-herein are used asterms of description and not of limitation, and there is no intention,in the use of such terms and expressions, of excluding any equivalentsof the features shown and described or portions thereof but it isrecognized that various modifications are possible within the scope ofthe invention claimed.

I claim:

l. A closure for containers defeating entry thereto by children andrelieving finger discomfort by pharmacists who must separate closuresfrom containers during container filling operations comprising-areversible closure body having first and second use positions on thesame container, the first use position protecting the interior of thecontainer from contamination and the second use position allowing theclosure to defeat entry by children, a first retainer means on a portionof the closure which is coupled to the container in said first useposition and being releasable therefrom by single simple manipulation ofthe closure, and a second retainer means on another portion of theclosure which is coupled to thecontainer in said second use position andrequiring a complex manipulation of the closure consisting of at leasttwo types of movement before separation of the closure from saidcontainer may be effected.

2. A closure for containers as defined by claim 1, wherein said firstretainer means is a friction means which releases easily from thecontainer by a simple force application, and said second retainer meansis a positive interlocking detent means on the closure which cooperateswith a positive locking element on a container and requires a movementof the closure to a position on the container where the detent means isaligned with a release passage in the locking element on the containerbefore separation of the closure from the container can be effected withthe closure in the second use position.

3. A closure for containers as defined by claim 2, wherein the firstretainer means is a plug element on said closure body adapted to enterthe mouth of a container and to be readily removable therefrom, and saidsecond retainer means comprises a skirt section on the closure bodyappliable over the mouth of a container externally of the mouth, andinterlocking lugs on the interior of said skirt section movable intopositive locking engagement with said positive locking element on thecontainer and separable therefrom by said movement of the closure tocause alignment of one of said lugs with said release passage.

4. The structure of claim 3, wherein said interlocking lugs are a pairof diametrically opposed lugs of unequal size with the smaller of saidlugs only adapted to pass 1 through said release passage,'both lugsadapted for posposition where the smaller lug is unaligned with saidresaid closure body and spanning a container mouth diametrically andonly partially plugging it.

7. The structure of claim 2, wherein said first retainer means comprisesa substantially annular skirt extension on the end of the closure whichis remote from the second retainer means and said skirt extensionappliable over the exterior of a container mouth to cover said mouthwhile the closure is in said first use position and while the secondretainer means is in an inactive position.

8. The structure of claim 7, and yielding internal detent means on saidskirt extension to interlock with said locking element on a container.

9. The structure of claim 8, and said internal detent means comprisingan internal annular bead on said skirt extension.

10. The structure of claim 8, and said internal detent means comprisinga pair of opposed lugs on the interior of the skirt extension.

11. The structure of claim 7, wherein said skirt extension is a thinwalled annular extension adapted to' snugly embrace and conform to theshape of said locking element on a container.

12. The structure of claim 2, wherein said first retainer means on theclosure comprises a friction plug element on the end of the closurewhich is remote from the second retainer means and a substantiallyannular skirt extension on the last-named closure end surrounding theplug element.

13. The structure of claim 12, and the plug element consisting of abar-like formation extending substantially diametrically on the closure.

14. The structure of claim 1, wherein the closure body comprises firstand second separated container coupling parts, said first retainer meansbeing on the first coupling part and the second retainer means being onthe second coupling part.

15. The structure of claim 14, and a transverse divider wall separatingthe first and second coupling parts of the closure and said divider walladapted to abut the end face of a container when the closure body is insaid first or second use positions.

16. The structure of claim 4, wherein said lugs additionally comprisescrew-threading elements on the closure adapted to cooperate with threadelements on a container inwardly of said container positive lockingelement.

17. A reversible closure having two positions of use on a containercomprising a first coupling part on said closure adapted to engage acontainer in one use position of the closure wherein the closureprotects the interior of the container from contamination, the firstcoupling part separating from the container by application thereto of asimple force, and a second coupling part on the closure having positiveinterlocking engagement with the container in the second position of useof the closure on the container, the second coupling part beingreleasable from the container only following a compound movement theretorelative to the container.

* i t i

1. A closure for containers defeating entry thereto by children andrelieving finger discomfort by pharmacists who must separate closuresfrom containers during container filling operations comprising areversible closure body having first and second use positions on thesame container, the first use position protecting the interior of thecontainer from contamination and the second use position allowing theclosure to defeat entry by children, a first retainer means on a portionof the closure which is coupled to the container in said first useposition and being releasable therefrom by single simple manipulation ofthe closure, and a second retainer means on another portion of theclosure which is coupled to the container in said second use positionand requiring a complex manipulation of the closure consisting of atleast two types of movement before separation of the closure from saidcontainer may be effected.
 2. A closure for containers as defined byclaim 1, wherein said first retainer means is a friction means whichreleases easily from the container by a simple force application, andsaid second retainer means is a positive interlocking detent means onthe closure which cooperates with a positive locking element on acontainer and requires a movement of the closure to a position on thecontainer where the detent means is aligned with a release passage inthe locking element on the container before separation of the closurefrom the container can be effected with the closure in the second useposition.
 3. A closure for containers as defined by claim 2, wherein thefirst retainer means is a plug element on said closure body adapted toenter the mouth of a container and to be readily removable therefrom,and said second retainer means comprises a skirt section on the closurebody appliable over the mouth of a container externally of the mouth,and interlocking lugs on the interior of said skirt section movable intopositive locking engagement with said positive locking element on thecontainer and separable therefrom by said movement of the closure tocause alignment of one of said lugs with said release passage.
 4. Thestructure of claim 3, wherein said interlocking lugs are a pair ofdiametrically opposed lugs of unequal size with the smaller of said lugsonly adapted to pass through said release passage, both lugs adapted forpositive interlocking engagement with said locking element on thecontainer when the closure is rotated to a position where the smallerlug is unaligned with said release passage.
 5. The structure of claim 3,wherein the plug element is a substantially circular element whichcompletely plugs the mouth of the container when placed therein.
 6. Thestructure of claim 3, wherein the plug element is an elongated bar-likeelement rising from one end of said closure body and spanning acontainer mouth diametrically and only partially plugging it.
 7. Thestructure of claim 2, wherein said first retainer means comprises asubstantially annular skirt extension on the end of the closure which isremote from the second retainer means and said skirt extension appliableover the exterior of a container mouth to cover said mouth while theclosure is in said first use position and while the second retainermeans is in an inactive position.
 8. The structure of claim 7, andyielding internal detent means on said skirt extension to interlock withsaid locking element on a container.
 9. The structure of claim 8, andsaid internal detent means comprising an internal annular bead on saidskirt extension.
 10. The structure of clAim 8, and said internal detentmeans comprising a pair of opposed lugs on the interior of the skirtextension.
 11. The structure of claim 7, wherein said skirt extension isa thin walled annular extension adapted to snugly embrace and conform tothe shape of said locking element on a container.
 12. The structure ofclaim 2, wherein said first retainer means on the closure comprises afriction plug element on the end of the closure which is remote from thesecond retainer means and a substantially annular skirt extension on thelast-named closure end surrounding the plug element.
 13. The structureof claim 12, and the plug element consisting of a bar-like formationextending substantially diametrically on the closure.
 14. The structureof claim 1, wherein the closure body comprises first and secondseparated container coupling parts, said first retainer means being onthe first coupling part and the second retainer means being on thesecond coupling part.
 15. The structure of claim 14, and a transversedivider wall separating the first and second coupling parts of theclosure and said divider wall adapted to abut the end face of acontainer when the closure body is in said first or second usepositions.
 16. The structure of claim 4, wherein said lugs additionallycomprise screw-threading elements on the closure adapted to cooperatewith thread elements on a container inwardly of said container positivelocking element.
 17. A reversible closure having two positions of use ona container comprising a first coupling part on said closure adapted toengage a container in one use position of the closure wherein theclosure protects the interior of the container from contamination, thefirst coupling part separating from the container by application theretoof a simple force, and a second coupling part on the closure havingpositive interlocking engagement with the container in the secondposition of use of the closure on the container, the second couplingpart being releasable from the container only following a compoundmovement thereto relative to the container.